The Curtiss Model L was a triplane produced as a trainer aircraft in the United States in 1916. A largely conventional design with the upper two wings of equal span and a shorter-span lower wing, the Model L had a wide open cockpit that accommodated the student and instructor side-by-side, an unusual feature for its time and which gained the aircraft the nickname of "Sociable Triplane". Apart from private sales, Curtiss sold a number to both the United States Army and Navy. These differed from their civil counterparts in having lower wings of equal span to the upper two. The three sold to the Navy were equipped as floatplanes.
The wings from one of the Army's examples were mated with the fuselage from a Curtiss Jenny to produce the single example of the X-1 trainer. Model L wings were also used by Curtiss in the creation of the Autoplane roadable aircraft, as well as mated to a Model F hull to create the Curtiss FL.